[FIXED] Possible bug in Phoenix/Amos Missile (Full Version)

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Ancalagon451 -> [FIXED] Possible bug in Phoenix/Amos Missile (2/6/2019 10:12:17 PM)

Recently I've been making some tests with Foxhounds and R-33 and gauged that, against fighter sized targets, maximum effective range is 40-50nm; due to the recent-ish requirement that the radar reflection is strongh enough for the smaller and less sensitive missile seeker to acquire the target.

When I tested the Tomcat with AIM-54 on the other hand, I discovered that it can shoot at maximum kinematic range against any target it can detect I.E. any non-stealthy plane.

Now if it where an AMRAAM type weapon that would be OK, since it's datalink guided. But, if I understand correctly, the AIM-54 employes SARH guiding for mid course correction, and so, It should be subjected to the same radar reflection requirements as any other SARH weapon, unless it is BOL launched which wasn't the case in my test.

Currently this seems not to be the case, so my question is: Is the AWG-9 radar powerful enough and/or the AIM-54 seeker sensitive enough to generate an acquirable reflection against a fighter-sized target at 120nm?

If that's not the case then there is some type of issue with the AIM-54 guidance model (perhaps being due to it's fairly unique nature)?

Ancalagon



Primarchx -> RE: Doubt About Phoenix Missile (2/6/2019 10:37:55 PM)

From https://fistofthefleet.org/wp-content/uploads/2016/01/Winter-2016.pdf
quote:

An F-14 could carry up to 6 Phoenix missiles, on LAU-93/A (F-14A/B) or LAU-132/A (F-14D) launchers, respectively. The AN/AWG-9 FCS uses a Track While Scan pulse-Doppler radar, and can track up to 24 targets simultaneously at ranges of up to 130 nm. Therefore, an F-14 can effectively attack 6 targets simultaneously. When an AIM-54A is launched, its Rocketdyne MK 47 or Aerojet MK 60 solid-fueled rocket motor propels it to a speed of Mach 4+. For mid-course guidance, the missile's AN/DSQ-26 guidance section employs an autopilot, which gets regular target position updates by semi-active radar tracking. The FCS radar periodically illuminates every target to which a missile has been dispatched. For maximum range, the missile flies an optimized high-altitude trajectory for reduced drag, and the AIM-54A can engage head-on targets at a distance of up to 72.5 nm. For the final 20,000 yd. of the interception the Phoenix switches to active radar homing for high terminal accuracy. Minimum engagement range is about 2 nm, in which case active homing is used from the beginning. The 132 lb. MK 82 blast-fragmentation warhead is
detonated by a fusing system consisting of a MK 334 radar proximity, an IR proximity, and an impact fuse. The AIM-54C features completely new digital WGU-11/B guidance and WCU-7/B control sections. The missile incorporates a programmable digital signal processor, and the autopilot now uses a strap-down inertial navigation system. One very important feature of the AIM-54C is its vastly improved ECCM capability. Improvements in the rocket motor increase speed and range, and the new DSU-28/B target detection device improves fusing accuracy in high-clutter environments and for small and low-altitude targets. ...


So you have a system that uses periodic SARH updates to an onboard autopilot/inertial guidance system to steer it close and then switches to an active homing radar for the last 10nm. AWG-9 / APG-71 were some of the most powerful radars ever put on a fighter a/c so generating an SARH return at a sizable range was probably not too hard, especially against their nominative foe, a Russian bomber.



Ancalagon451 -> RE: Doubt About Phoenix Missile (2/6/2019 11:03:10 PM)

Yeah, but the point here it's that I tested against it a russian fighter, and a fairly small one at that (mig-21bis) and it gave me an acquirable reflection at two and half times the range compared to a radar that performs at near the same performance (initial detection ranges where 115nm for the AWG-9 vs 95nm for the Zaslon).

That difference seems simply exceesive to me, so while perhaps you are correct and the AWG-9 it's a much superior set, It could also be a game bug.

So I would prefer that a Dev confirms one way of another.

Ancalagon

Also the testbed I employed:



AndrewJ -> RE: Doubt About Phoenix Missile (2/6/2019 11:48:54 PM)

This also came up a few months ago, after some tweaks because of problems with the MiG-31/AA-9 combo back in October.

I tried out a number of different planes, and my conclusion wasn't that the F-14/Phoenix combo was exceptionally good, but rather that the MiG-31/AA-9 combo had become anomalously bad. While it used to be effective out near max range, much like the Phoenix, now it can only achieve around 52 nm.

Here's comparative results of testing different SARH systems (F-4, F-15, MiG-25, F-14, MiG-31) vs fighter and bomber targets.

[img]https://i.imgur.com/dI7jIzi.png[/img]

You can see how the MiG-31 system is proportionately much worse than other systems. It's only detecting the fighter targets at ~ 42% of its maximum radar range, compared with 70% or 82% or 84% or 91% for an F-4 or F-14 or F-15 or MiG-25, and its only illuminating at ~ 31% of its maximum range. If it acted in similar proportion to the other systems, you would expect detections out around the 120 to 150 nm range. The slightly older F-14 is getting 147 nm detections, so why not the Mig-31? It's only getting half the F-14's detection range (and that's purely a radar issue, before the missile enters the equation).

[img]https://i.imgur.com/8TjicjG.png[/img]

Spot the outlier!

Look-down clutter is not a differentiating issue here, since the planes in the test scenario are all at the same altitude. I also tried with the MiG-31 one altitude band lower than the target, and got the same range results.

The fact that the MiG-31 system had a lower range than the F-15/Sparrow system seems counter-intuitive. The raw power of the Flash Dance is significantly higher (1.7 times more range) than the AN/APG-70, and the antenna on the missile is also significantly larger. The AA-9 has a 15" diameter body, while the Sparrow is only 8". For a crude order of magnitude comparison, knocking off 1" for radome thickness and antenna clearance, the AA-9 has roughly four times more signal gathering antenna area than the Sparrow. Wouldn't that mean it could detect the same echo at roughly twice the range?

So I think the question is not "why is the F-14 so good?", but rather "why did the MiG-31 become unusually bad?"



Amnectrus -> RE: Doubt About Phoenix Missile (2/10/2019 2:22:50 AM)

I just tried a quick test with a MiG-31 (1982 model with "Flash Dance [N-007 Zaslon]" radar) against an F-15C (1984 model with "AN/APG-63" radar) flying head-on toward each other. The MiG-31 detected the F-15C at 125 miles, or 73% of its max range. It was able to fire at 54 miles, so that part was the same, but I had a much longer detection distance. Intuitively, I agree that it does seem like a longer detection distance combined with a larger missile antenna should give a longer possible engagement range though.



Filitch -> RE: Doubt About Phoenix Missile (2/10/2019 2:43:41 PM)

Sorry, I write here, not in the special thread for DB requests. But I would put all request on Foxbat's radar together. As I can see, in the database all versions of N-007 (ID 877, 2517, 5193) has 2 Maximal contacts illuminate. But Zaslon (ID 877) and Zaslon-A (ID 2517) can illuminate 4 contacts. Source: http://militaryrussia.ru/blog/topic-407.html
Zaslon-M (ID 5193) can illuminate 6 contacts. Source: http://militaryrussia.ru/blog/topic-651.html, Y.Gordon "Mikoyan MiG-31"
Moreover, nominal detection range of Zaslon-M, by different sources, is 195-215 nm.



Ancalagon451 -> RE: Doubt About Phoenix Missile (2/28/2019 9:06:59 PM)

Bumping this just to make sure it's been queued for revision, since it seems like the Phoenix it's gonna have a prominent place in the next DLC campaign.

If it was already queued then sorry for the bother.

Ancalagon



Dimitris -> RE: Doubt About Phoenix Missile (3/1/2019 4:33:34 AM)

Yes, the Zaslon has been given some updates on the next version of the DB3000 database.



Ancalagon451 -> RE: Doubt About Phoenix Missile (3/1/2019 9:13:08 AM)

So, it really was a problem of Zaslon underpowered and not of AWG-9 overpowered?

Anyway, glad to know it's been corrected, thanks for your continuous work.

Ancalagon



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